TWI507108B - Flexible circuit board and method for manufacturing same - Google Patents

Description

Flexible circuit board and manufacturing method thereof

The present invention relates to a method of fabricating a flexible circuit board, and more particularly to a printed circuit board having an optical identification block and a method of fabricating the same.

At present, the prior art generally uses Surface Mounting Technology (STM) to solder electronic components on a printed circuit board. Generally, when confirming the soldering position of the printed circuit board, the optical identification method is adopted. The principle of the optical recognition method is to set an identification block different from the surrounding color on the printed circuit board, and the color difference between the identification block and the surrounding color is more Large, the better the recognition effect.

In the prior art, most of the layers are covered with a layer of metal at the position of the identification block, or the printing ink is blackened, and the color difference between the identification block and the surrounding color is large. The use of ink coating to blacken the identification block, the ink is easy to scatter and affect the soldering; the process of covering the metal is usually a gold-plated method using a lead wire. This method makes the surface mounter easy to produce optical recognition due to the presence of the lead wire. error.

It is an object of the present invention to provide a flexible circuit board having an optical identification block that does not require the application of ink or metal and a method of fabricating the same.

A method for fabricating a flexible circuit board, comprising the steps of: providing a double-sided copper-clad substrate, the double-sided copper-clad substrate comprising a transparent first dielectric layer and disposed on the first dielectric a first copper foil layer and a second copper foil layer on opposite sides of the layer, wherein the surfaces of the first copper foil layer and the second copper foil layer contacting the first dielectric layer are respectively a first blackened surface and a second blackening surface; partially etching the first copper foil layer and the second copper foil layer to form a first conductive wiring layer and a second conductive wiring layer, and etching a first opening in the first copper foil layer, The second copper foil layer is not etched away for the first opening portion to form a circuit substrate; a first single-sided copper foil substrate is provided, and the first single-sided copper foil substrate includes a transparent second dielectric layer An electric layer and a third copper foil layer attached to one side of the second dielectric layer, the first single-sided copper foil substrate is press-bonded to the first conductive circuit layer, the second dielectric layer Adjacent to the first conductive wiring layer; and partially etching the third copper foil layer to form a third conductive wiring layer, wherein the third conductive wiring layer has a first opening corresponding to the first conductive wiring layer a third opening region, the central region of the third opening region having an unetched copper foil region, forming a Identifying blocks forming a flexible circuit board.

A method for fabricating a flexible circuit board, comprising the steps of: providing a double-sided copper-clad substrate, wherein the double-sided copper-clad substrate comprises a transparent first dielectric layer and a first surface disposed on opposite sides of the first dielectric layer a copper foil layer and a second copper foil layer, wherein the surfaces of the first copper foil layer and the second copper foil layer contacting the first dielectric layer are a first blackened surface and a second blackened surface, respectively; The first copper foil layer and the second copper foil layer are partially etched to form a first conductive wiring layer and a second conductive wiring layer, respectively, and the first copper foil layer has a fifth opening area, the second A portion of the copper foil layer facing the fifth opening region is not etched away, and a copper foil region is formed in a central region of the opening region to constitute a third identification block, thereby forming a flexible circuit board.

A flexible circuit board comprising a transparent first dielectric layer, a first conductive circuit layer and a second conductive circuit layer disposed on opposite sides of the first dielectric layer, formed on the first a transparent second dielectric layer on a conductive wiring layer and a third conductive wiring layer formed on the second dielectric layer. The surfaces of the first conductive circuit layer and the second conductive circuit layer contacting the first dielectric layer are respectively a first blackened surface and a second blackened surface, and the first conductive circuit layer has a first opening The third conductive circuit layer has a third opening area corresponding to the first opening, and a central area of the third opening area has a copper foil area constituting the first identification block.

A flexible circuit board includes a transparent first dielectric layer and a first conductive circuit layer and a second conductive circuit layer disposed on opposite sides of the first dielectric layer. a surface of the first conductive circuit layer and the second conductive circuit layer contacting the first dielectric layer is a first blackening surface and a second blackening surface, respectively, and the first conductive circuit layer has a fifth opening And a portion of the second conductive circuit layer corresponding to the fifth opening region is not etched away, and a central portion of the fifth opening region has a copper foil region to constitute a third identification block.

Compared with the prior art, the color difference between the first recognition block of the flexible circuit board of the present invention and the first background area around it is large, so that the first recognition area can be easily identified, and the optical recognition effect is good. The flexible circuit board can be accurately identified and positioned during processes such as surface mount. In addition, the invention does not need to increase the steps of coating ink, plating metal, etc. under the premise of ensuring accurate identification of the position, thereby simplifying the process. The flexible circuit board of the present invention can be used to fabricate rigid-flex bonded circuit boards.

100‧‧‧Flexible circuit board

110‧‧‧Line substrate

120‧‧‧Double-sided copper clad substrate

1200‧‧‧Two-layer circuit board

121‧‧‧First copper foil layer

122‧‧‧Second copper foil layer

123‧‧‧First dielectric layer

1210‧‧‧First conductive circuit layer

1220‧‧‧Second conductive circuit layer

130‧‧‧First single-sided copper foil substrate

131‧‧‧ Third copper foil layer

1310‧‧‧ Third conductive circuit layer

132‧‧‧Second dielectric layer

230‧‧‧Second single-sided copper foil substrate

231‧‧‧fourth copper foil layer

2310‧‧‧fourth conductive layer

232‧‧‧ third dielectric layer

133‧‧‧3rd opening area

134‧‧‧fourth opening area

135‧‧‧First identification block

136‧‧‧Second identification block

137‧‧‧ Third identification block

138‧‧‧5th opening area

141‧‧‧ first opening

142‧‧‧ second opening

151‧‧‧First blackened surface

152‧‧‧Second blackened surface

160‧‧‧First background area

1 is a cross-sectional view of a double-sided copper-clad substrate according to an embodiment of the present invention.

2 is a cross-sectional view showing a wiring substrate formed by etching a copper foil layer of the double-sided copper-clad substrate of FIG. 1 to form a conductive wiring layer.

Figure 3 is a cross-sectional view showing the first and second single-sided copper foil substrates pressed into the first conductive wiring layer of Figure 2 .

4 is a cross-sectional view showing a flexible circuit board formed by forming the first and second single-sided copper foil substrates of FIG. 3 to form a conductive wiring layer, and forming the identification block on the first single-sided copper foil substrate.

5 is a cross-sectional view showing a flexible circuit board formed by forming the first and second single-sided copper foil substrates of FIG. 3 to form a conductive wiring layer and an identification block.

Figure 6 is a cross-sectional view of the flexible circuit board formed after the identification block is formed on the first conductive wiring layer of Figure 2.

Fig. 7 is a view showing the effect of chromatic aberration between the second identification block and the opening area as viewed from the side of the flexible circuit board of Fig. 4.

Embodiments of the present invention provide a method for fabricating a flexible circuit board, including the steps of:

In the first step, referring to FIG. 1, a double-sided copper clad substrate 120 is provided.

The double-sided copper clad substrate 120 includes a first dielectric layer 123 and a first copper foil layer 121 and a second copper foil layer 122 disposed on opposite sides of the first dielectric layer 123. The surfaces of the first copper foil layer 121 and the second copper foil layer 122 that are in contact with the first dielectric layer 123 are a first blackening surface 151 and a second blackening surface 152, respectively. The first blackening surface 151 and the second blackening surface 152 are black surfaces formed on the surface of the copper foil by a black roughening technique to improve the bonding strength of the copper foil layer to the substrate. In this embodiment, the black surface is a layer of black ultra-fine copper-arsenic alloy, which is generally formed by the manufacturer of the copper-clad substrate when supplied to the circuit board manufacturer. In this embodiment, the first dielectric layer 123 may be a transparent polyimide film.

In the second step, referring to FIG. 2, the first copper foil layer 121 and the second copper foil layer 122 are partially etched to form a first conductive wiring layer 1210 and a second conductive wiring layer 1220, respectively, and in the first copper foil. The edge region of the layer 121 etches the first opening 141, thereby forming a wiring substrate 110.

In this embodiment, the first opening 141 is circular. The portion of the second copper foil layer 122 that is not etched away from the first opening 141, that is, the second blackened surface is observed through the first dielectric layer 123 from the side of the first conductive wiring layer 1210. 152.

It can be understood that the second opening 142 can be etched in the edge region of the second conductive circuit layer 1220 while etching the second copper foil layer 122 to form the second conductive wiring layer 1220. In a circular shape, a portion of the first copper foil layer 121 facing the second opening 142 is not etched away, that is, the first dielectric layer 123 is observed from the second conductive wiring layer 1220 side. The first blackened surface 151 is described.

In the third step, referring to FIG. 3, a first single-sided copper foil substrate 130 and a second single-sided copper foil substrate 230 are provided, and the first single-sided copper foil substrate 130 and the second single-sided copper foil substrate 230 are respectively pressed. The first conductive circuit layer 1210 and the second conductive circuit layer 1220 are combined.

In this embodiment, the first single-sided copper foil substrate 130 includes a second dielectric layer 132 and a third copper foil layer 131 disposed on the surface of the second dielectric layer 132; the second single-sided copper foil substrate 230 The third dielectric layer 232 and the fourth copper foil layer 231 disposed on the surface of the third dielectric layer 232 are included. The second dielectric layer 132 is adjacent to the first conductive wiring layer 1210, and the third dielectric layer 232 is adjacent to the second conductive wiring layer 1220. The material in the second dielectric layer 132 and the third dielectric layer 232 fills the gap between the conductive lines of the corresponding first conductive circuit layer 1210 and the first opening 141, The gap between the conductive lines of the second conductive circuit layer 1220 and the second opening 142. In this embodiment, the material in the second dielectric layer 132 and the third dielectric layer 232 is a transparent polyimide material. Of course, the materials of the second dielectric layer 132 and the third dielectric layer 232 may further be provided with a transparent adhesive to better adhere the second dielectric layer 132 and the third dielectric layer 232 to the adjacent structures. Fixed.

In the fourth step, referring to FIG. 4, the third copper foil layer 131 is partially etched to form a third conductive circuit layer 1310, and the fourth copper foil layer 231 is partially etched to form a fourth conductive circuit layer 2310 to form a flexible circuit. Board 100. The third conductive circuit layer 1310 has a circular third opening region 133 corresponding to the first opening 141 of the first conductive circuit layer 1210. The central region of the third opening region 133 has a circular shape. The copper foil region that is not etched constitutes the first identification block 135.

It can be understood that, referring to FIG. 5, a fourth annular opening region 134 may be further formed at the second opening 142 of the fourth conductive circuit layer 2310 corresponding to the second conductive circuit layer 1220, the fourth The central region of the open region 134 has a circular, unetched copper foil region that forms the second identification block 136.

In this embodiment, the third opening region 133 is annular. The first identification block 135 is a circular copper foil, and the surface of the first identification block 135 away from the second dielectric layer 132 is yellow. In this embodiment, the outer diameter of the third opening region 133 is the same as the diameter of the first opening 141 and is coaxial.

It can be understood that the third opening area 133 may be other regular or irregular shapes, such as a rectangle, a square, an ellipse, etc., and the third opening area 133 is preferably a center-symmetrical shape. The first identification block 135 may also have other shapes, such as a center-symmetric shape such as a rectangle, a square, an ellipse, an equilateral triangle, etc., and is not limited to this embodiment.

Referring to FIG. 4, the first dielectric layer 123 and the second dielectric layer 132 are transparent. The color of the second blackened surface 152 is observed through the second dielectric layer 132 and the first dielectric layer 123 at the third opening region 133 as viewed from the side of the third conductive wiring layer 1310. With further reference to FIG. 7, the second blackened surface 152 that is observed forms a first background region 160 around the first identification block 135. In this embodiment, the first background region 160 is annular, and because the color of the second blackening surface 152 is black, the color of the first background region 160 is black, and the first recognition The color of the block 135 is yellow, and the first recognition block 135 can be identified by a large color difference between yellow and black.

It can be understood that, referring to FIG. 6, the embodiment of the present invention may further be a two-layer circuit board 1200, which forms a third on the first conductive circuit layer 1210 or/and the second conductive circuit layer 1220. The identification block 137 and the corresponding fifth opening region 138, the color of the second blackening surface 152 and/or the first blackening surface 151 are observed through the first dielectric layer 123 and the fifth opening region 138, Thereby, the third identification block 137 can be identified.

It can be understood that a conductive circuit layer may be further disposed between the first conductive circuit layer 1210 and the third conductive circuit layer 1310 and/or between the second conductive circuit layer 1220 and the fourth conductive circuit layer 2310 according to actual conditions, as long as The second blackened surface 152 of the second conductive wiring layer 1220 can be observed from the side of the third opening region 133 so that the first identification block 135 can be identified, and is not limited to the embodiment.

As shown in FIG. 4, the flexible circuit board 100 of the present embodiment includes a first dielectric layer 123, a first conductive circuit layer 1210 and a second conductive circuit layer 1220 disposed on opposite sides of the first dielectric layer 123, and is formed on a second dielectric layer 132 on the first conductive wiring layer 1210 and a third conductive wiring layer 1310 formed on the second dielectric layer 132. The third conductive circuit layer 1310 further includes a first identification block 135.

The flexible circuit board 100 further includes a third dielectric layer 232 formed on the second conductive wiring layer 1220 and a fourth conductive wiring layer 2310 formed on the third dielectric layer 232.

Compared with the prior art, the color difference between the first recognition block 135 of the flexible circuit board 100 of the present invention and the surrounding first background area 160 is large, so that the first identification block 135 can be easily identified, and the optical recognition effect is good. The flexible circuit board 100 can be accurately identified and positioned during a process such as surface mounting. In addition, the invention does not need to increase the steps of coating ink, plating metal, etc. under the premise of ensuring accurate identification of the position, thereby simplifying the process.

In summary, the present invention complies with the requirements of the invention patent and submits a patent application according to law. However, the above description is only the preferred embodiment of the present invention, and equivalent modifications or variations made by those skilled in the art will be covered by the following claims.

100‧‧‧Flexible circuit board

123‧‧‧First dielectric layer

1210‧‧‧First conductive circuit layer

1220‧‧‧Second conductive circuit layer

1310‧‧‧ Third conductive circuit layer

2310‧‧‧fourth conductive layer

133‧‧‧3rd opening area

135‧‧‧First identification block

152‧‧‧Second blackened surface

Claims (10)

A method for fabricating a flexible circuit board, comprising the steps of: providing a double-sided copper-clad substrate, wherein the double-sided copper-clad substrate comprises a transparent first dielectric layer and a first surface disposed on opposite sides of the first dielectric layer a copper foil layer and a second copper foil layer, wherein the surfaces of the first copper foil layer and the second copper foil layer in contact with the first dielectric layer are respectively a first blackened surface and a second blackened surface; The first copper foil layer and the second copper foil layer are partially etched to form a first conductive wiring layer and a second conductive wiring layer, respectively, and a first opening is etched in the first copper foil layer, the second copper foil layer The central portion is not etched away from the first opening portion to form a circuit substrate; the first single-sided copper foil substrate is provided, and the first single-sided copper foil substrate comprises a transparent second dielectric layer and is bonded to the same a third copper foil layer on a side of the second dielectric layer, the first single-sided copper foil substrate is pressed onto the first conductive circuit layer, the second dielectric layer and the first conductive line Adjacent to the layer; and partially etching the third copper foil layer to form a third conductive wiring layer at the third conductive line Layer corresponds to first wiring layer having a third opening of the first opening region, the central region of the third opening region has a region not etched copper foil, constituting the first identification block, forming a flexible circuit board. The method of fabricating a flexible circuit board according to claim 1, wherein the second conductive wiring layer has a second opening, and a portion of the first copper foil layer facing the second opening is not etched away. The method of fabricating a flexible circuit board according to claim 1, wherein a transparent third dielectric layer and a fourth conductive wiring layer are sequentially formed on the second conductive wiring layer side, and the second conductive wiring layer has a first a second opening, the fourth conductive circuit layer corresponding to the second opening has a fourth The opening area, the central area of the fourth opening area has a copper foil area, and constitutes a second identification block. The manufacturing method of the flexible circuit board of claim 1, wherein the shape of the first opening is a center symmetrical shape, the shape of the third opening area and the first identification block is a center symmetrical shape, and The shape of the first opening is the same as the shape of the third opening area. A method for fabricating a flexible circuit board, comprising the steps of: providing a double-sided copper-clad substrate, wherein the double-sided copper-clad substrate comprises a transparent first dielectric layer and a first surface disposed on opposite sides of the first dielectric layer a copper foil layer and a second copper foil layer, wherein the surfaces of the first copper foil layer and the second copper foil layer contacting the first dielectric layer are a first blackened surface and a second blackened surface, respectively; The first copper foil layer and the second copper foil layer are partially etched to form a first conductive wiring layer and a second conductive wiring layer, respectively, and the first copper foil layer has a fifth opening area, the second A portion of the copper foil layer facing the fifth opening region is not etched away, and a copper foil region is formed in a central region of the opening region to constitute a third identification block, thereby forming a flexible circuit board. The method of fabricating a flexible circuit board according to claim 5, wherein, further, the second copper foil layer has a sixth opening, and the portion of the first copper foil layer facing the sixth opening region Not etched away, having a copper foil region in the central region of the sixth opening to form a fourth identification block. A flexible circuit board comprising a transparent first dielectric layer, a first conductive circuit layer and a second conductive circuit layer disposed on opposite sides of the first dielectric layer, and formed on the first conductive circuit layer a transparent second dielectric layer and a third conductive circuit layer formed on the second dielectric layer, a surface of the first conductive circuit layer and the second conductive circuit layer in contact with the first dielectric layer a first blackened surface and a second blackened surface, respectively, the first conductive circuit layer has a first opening, and the third conductive circuit layer has a third open area corresponding to the first opening, the first The central area of the three open areas has a copper foil area that constitutes the first identification block. The flexible circuit board of claim 7, wherein the flexible circuit board further comprises a transparent third dielectric layer formed on the second conductive wiring layer and a first surface formed on the third dielectric layer a fourth conductive circuit layer, the second conductive circuit layer has a second opening, the fourth conductive circuit layer has a fourth opening region corresponding to the second opening, and a central region of the fourth opening region has a copper The foil area constitutes a second identification block. A flexible circuit board comprising a transparent first dielectric layer and a first conductive circuit layer and a second conductive circuit layer disposed on opposite sides of the first dielectric layer, the first conductive circuit layer and the second conductive circuit layer The surface in contact with the first dielectric layer is a first blackened surface and a second blackened surface, respectively, the first conductive circuit layer has a fifth open area, and the second conductive circuit layer corresponds to the A portion of the fifth opening region is not etched away, and a central region of the fifth opening region has a copper foil region constituting a third identification block. The flexible circuit board of claim 9, wherein the flexible circuit board further comprises a sixth opening formed in the second conductive circuit layer, the first conductive circuit layer corresponding to a portion of the sixth opening Not etched away, the central region of the sixth opening has a copper foil region to form a fourth identification block.